Supernova 1987A Trace Shock Wave

This image shows the entire region around supernova 1987A. The most prominent feature in the
image is a ring with dozens of bright spots. A shock wave of material unleashed by the stellar
blast is slamming into regions along the ring’s inner regions, heating them up, and causing them
to glow. The ring, about a light-year across, was probably shed by the star about 20,000 years
before it exploded.